Hydrochloric Acid → (S)-3-cyclopentyl-N-[1-(2-hydroxy-2-methyl-propyl)-1H-pyrazol-3-yl]-2-[4-((S)-2-methoxy-1-methyl-ethoxy)-2-oxo-2,5-dihydro-pyrrol-1-yl]-propionamide

Participants

Reaction Steps

A solution of (S)-3-cyclopentyl-N-[1-(2-hydroxy-2-methyl-propyl)-1H-pyrazol-3-yl]-2-(4-methoxy-2-oxo-2,5-dihydro-pyrrol-1-yl)-propionamide (prepared as in Example 1, 35 mg, 0.09 mmol) in a hydrochloric acid (gas) saturated acetic acid (5 mL) solution was heated in a sealed tube at 75° C. for 2 h. After that, the reaction mixture was cooled to room temperature, and concentrated. The residue was added to (S)-1-methoxy-propan-2-ol (162 mg, 1.76 mmol), and toluene-4-sulfonic acid hydrate (10 mg). The mixture was heated to 90° C., for 18 h. The reaction mixture was concentrated and the residue was dissolved in dichloromethane. The organic layer was washed with saturated sodium bicarbonate solution, saturated sodium chloride solution, and dried over magnesium sulfate. The crude product was purified using reverse phase HPLC (Biosystems MDS-SCIEX LC/MS, Pursuit C-18 2×10 mm, water/acetonitrile 0.05% trifluoroacetic acid) to afford (S)-3-cyclopentyl-N-[1-(2-hydroxy-2-methyl-propyl)-1H-pyrazol-3-yl]-2-[4-((S)-2-methoxy-1-methyl-ethoxy)-2-oxo-2,5-dihydro-pyrrol-1-yl]-propionamide (3 mg, 9%) as a white foam: LR-ES-MS m/z calculated for C23H36N4O5 [M]+ 448, observed [M+H]+ 449; 1H NMR (300 MHz, CDCl3) δ ppm 1.08-1.25 (m, 2H) 1.16 (s, 6H) 1.32 (d, J=6.3 Hz, 3H) 1.43-2.07 (m, 9H) 3.40 (s, 3H) 3.44-3.59 (m, 2H) 3.66 (br. s., 1H) 3.90-4.00 (d, J=17.8 Hz, 1H) 3.95 (s, 2H) 4.08 (d, J=17.8 Hz, 1H) 4.34-4.47 (m, 1H) 4.80 (dd, J=8.9, 6.5 Hz, 1H) 5.12 (s, 1H) 6.67 (d, J=2.0 Hz, 1H) 7.30 (d, J=2.0 Hz, 1H) 8.85 (br. s., 1H).

Provenance & Evidence